1. Field of Invention
This invention relates to aircraft flight control systems and more particularly to such systems including a walking beam in its control linkage system and with provisions for imparting a pilot input and at least one other input to the walking beam so as to produce an output control signal therefrom and with provisions to permit the pilot to continue controlling the aircraft through the walking beam should one or more of the other input controls to the walking beam become inoperative or jammed, and also including mechanism to prevent the pilot from imparting an over-control to the aircraft in the process of initially controlling the aircraft with the other control input to the walking beam jammed.
2. Description of the Prior Art
In the aircraft flight control art, it is known to include walking beams in the flight control linkage system and to impart both pilot controlled and other controlled input signals thereto, and to fabricate the walking beam in two pieces joined by a shear pin so that the walking beam normally operates as a unitary beam and so that, in response to pilot input force, the shear pin can be sheared or ruptured should the other input to the walking beam become jammed, thereby permitting the pilot to control the aircraft with the portion of the walking beam so freed. This is shown in assignees U.S. Pat. No. 3,908,513 to Leoni. It is also known in the control art to utilize springs or other continuously operating mechanism to provide resistance to input commands or signals to the control, such as in Marichal U.S. Pat. No. 556,547, however, such mechanisms continue in operation after the over-control threat has passed and therefore continuously adversely affect normal operation of the control system thereafter.